Spectroscopic And Electrochemical Behavior Of The Double Nuclear Sulfonated Cobalt Phthalocyanine

Spectra and electrochemistry of binuclear cobalt phthalocyaninehexasulfonate(bi-CoPc) in nonaqueous solution: dimethylformamide(DMF), dimethylsulfoxide(DMSO), aqueous solution and mixed solution were studied in this paper. The aggregation mechanism of bi-CoPc in aqueous solution was studied by the electronic absorption spectra in the visible region, and the electrochemistry and electrocatalysis of bi-CoPc were accomplished in liquid crystal film of didodecyldimethylammonium bromide(DDAB) on pyrolytic graphite(PG) electrode in aqueous solution. The results herein show:(1) The better electrochemistry of bi-CoPc were investigated in DMF and DMSO, and the Co!I/Co' redox couple splits into two couples in DMSO.(2) A heavy aggregation of bi-CoPc in aqueous solution because of hydrogen bond can be reduced by producing bi-CoPc-DDAB film electrode or by making mixed solution. Different forms of bi-CoPc in aqueous solution, DDAB film and mixed solution were observed with electron-microscope.(3) The charge transport diffusion coefficient, DC, and apparent heterogenous electrode reaction rate constant, ks, in DMF and DDAB film systems were estimated by CV respectively, and the surface coverage was evaluated. The comproportionation costant, Kc, of compound ConPc(-3)CoJPc(-3)was caculated according to the splitting energy.(4) The reduction of bi-CoPc ligand catalyzed the reduction of trichloroacetic acid(rC4) and catalytic current had a linear relationship with the concentration of TCA in the range of 3X 10~5~7.5X 10~3mol/L. The reduction of bi-Co(III)Pc/bi-Co(II)Pc couple mediate the reduction of oxygen.